The origins of the HDI are found in the annual Human Development Reports produced by the Human Development Reports Office of the United Nations Development Programme (UNDP). These were devised and launched by Pakistani economist Mahbub ul Haq in 1990, and had the explicit purpose "to shift the focus of development economics from national income accounting to people-centered policies". To produce the Human Development Reports, Mahbub ul Haq formed a group of development economists including Paul Streeten, Frances Stewart, Gustav Ranis, Keith Griffin, Sudhir Anand, and Meghnad Desai. Working alongside Nobel laureate Amartya Sen, they worked on capabilities and functions that provided the underlying conceptual framework. Haq was sure that a simple composite measure of human development was needed in order to convince the public, academics, and politicians that they can and should evaluate development not only by economic advances but also improvements in human well-being. Sen initially opposed this idea, but he was helped by Haq in order to develop the Index. Sen was worried that it was going to be difficult to capture the full complexity of human capabilities in a single index, but Haq insisted that only a single number would shift the immediate attention of politicians from economic to human well-being.[1][2]

The formula defining the HDI is promulgated by the United Nations Development Programme (UNDP).[7] In general, to transform a raw variable, say x{\displaystyle x}, into a unit-free index between 0 and 1 (which allows different indices to be added together), the following formula is used:

The 2015 Human Development Report by the United Nations Development Programme was released on December 14, 2015, and calculates HDI values based on estimates for 2014. Below is the list of the "very high human development" countries:[8][9][10]

= increase.

= steady.

= decrease.

The number in brackets represents the number of ranks the country has climbed (up or down) relative to the ranking in 2014 report.

The 2014 Human Development Report by the United Nations Development Programme was released on July 24, 2014, and calculates HDI values based on estimates for 2013. Below is the list of the "very high human development" countries:[14][9][10]

= increase.

= steady.

= decrease.

The number in brackets represents the number of ranks the country has climbed (up or down) relative to the ranking in 2013 report.

The Inequality-adjusted Human Development Index (IHDI)[14] is a "measure of the average level of human development of people in a society once inequality is taken into account."

Note: The green arrows (), red arrows (), and blue dashes () represent changes in rank. The changes in rank are not relative to the HDI list above, but are according to the source (p. 168) calculated with the exclusion of countries which are missing IHDI data.

The 2013 Human Development Report by the United Nations Development Program was released on March 14, 2013, and calculates HDI values based on estimates for 2012. Below is the list of the "very high human development" countries:[16]

Note: The green arrows (), red arrows (), and blue dashes () represent changes in rank when compared to the new 2012 data HDI for 2011 – published in the 2012 report.

The Inequality-adjusted Human Development Index (IHDI)[16] is a "measure of the average level of human development of people in a society once inequality is taken into account."

Note: The green arrows (), red arrows (), and blue dashes () represent changes in rank. The changes in rank are not relative to the HDI list above, but are according to the source (p. 152) calculated with the exclusion of countries which are missing IHDI data.

The 2011 Human Development Report was released on 2 November 2011, and calculated HDI values based on estimates for 2011. Below is the list of the "very high human development" countries (equal to the top quartile):[17]

Note: The green arrows (), red arrows (), and blue dashes () represent changes in rank when compared to the 2011 HDI data for 2010 – published in the 2011 report (p. 131).

Below is a list of countries in the top quartile by Inequality-adjusted Human Development Index (IHDI).[18] According to the report, the IHDI is a "measure of the average level of human development of people in a society once inequality is taken into account."

Note: The green arrows (), red arrows (), and blue dashes () represent changes in rank when compared to the 2011 HDI list, for countries listed in both rankings.

The 2010 Human Development Report by the United Nations Development Program was released on November 4, 2010, and calculates HDI values based on estimates for 2010. Below is the list of the "very high human development" countries:[20]

Note: The green arrows (), red arrows (), and blue dashes () represent changes in rank when compared to the 2009 HDI published in the 2010 report.

The 2010 Human Development Report was the first to calculate an Inequality-adjusted Human Development Index (IHDI), which factors in inequalities in the three basic dimensions of human development (income, life expectancy, and education). Below is a list of countries in the top quartile by IHDI:[21]

Note: The green arrows (), red arrows (), and blue dashes () represent changes in rank when compared to the 2010 HDI list, for countries listed in both rankings.

Some countries were not included for various reasons, mainly the unavailability of certain crucial data. The following United Nations Member States were not included in the 2010 report.[19]Cuba lodged a formal protest at its lack of inclusion. The UNDP explained that Cuba had been excluded due to the lack of an "internationally reported figure for Cuba's Gross National Income adjusted for Purchasing Power Parity". All other indicators for Cuba were available, and reported by the UNDP, but the lack of one indicator meant that no ranking could be attributed to the country.[23][24] The situation has been addressed and, in later years, Cuba has ranked as a High Human Development country.

The 2009Human Development Report by the UNDP was released on October 5, 2009, and covers the period up to 2007. It was titled "Overcoming barriers: Human mobility and development". The top countries by HDI were grouped in a new category called "very high human development". The report refers to these countries as developed countries. They are:[25]

Some countries were not included for various reasons, such as being a non-UN member or unable or unwilling to provide the necessary data at the time of publication. Besides the states with limited recognition, the following states were also not included.

A new index was released on December 18, 2008. This so-called "statistical update" covered the period up to 2006 and was published without an accompanying Human Development Report. The update is relevant due to newly released estimates of purchasing power parities (PPP), implying substantial adjustments for many countries, resulting in changes in HDI values and, in many cases, HDI ranks.[26]

Some countries were not included for various reasons, such as being a non-UN member, unable, or unwilling to provide the necessary data at the time of publication. Besides the states with limited recognition, the following states were also not included.[28]

The Human Development Report for 2007/2008 was launched in Brasília, Brazil, on November 27, 2007. Its focus was on "Fighting climate change: Human solidarity in a divided world."[29] Most of the data used for the report are derived largely from 2005 or earlier, thus indicating an HDI for 2005. Not all UN member states choose to or are able to provide the necessary statistics.

A HDI below 0.5 is considered to represent "low development". All 22 countries in that category are located in Africa. The highest-scoring Sub-Saharan countries, Gabon and South Africa, are ranked 119th and 121st, respectively. Nine countries departed from this category this year and joined the "medium development" group.

On the following table, green arrows () represent an increase in ranking over the previous study, while red arrows () represent a decrease in ranking. They are followed by the number of spaces they moved. Blue dashes () represent a nation that did not move in the rankings since the previous study.

The list below displays the top-ranked country from each year of the Human Development Index. Norway has been ranked the highest twelve times, Canada eight times, followed by Japan which has been ranked highest three times. Iceland has been ranked highest twice.

The Human Development Index has been criticized on a number of grounds including alleged ideological biases towards egalitarianism and so-called "Westernmodels of development", failure to include any ecological considerations, lack of consideration of technological development or contributions to the human civilization, focusing exclusively on national performance and ranking, lack of attention to development from a global perspective, measurement error of the underlying statistics, and on the UNDP's changes in formula which can lead to severe misclassification in the categorisation of 'low', 'medium', 'high' or 'very high' human development countries.[31]

Economists Hendrik Wolff, Howard Chong and Maximilian Auffhammer discuss the HDI from the perspective of data error in the underlying health, education and income statistics used to construct the HDI.[31] They identified three sources of data error which are due to (i) data updating, (ii) formula revisions and (iii) thresholds to classify a country's development status and conclude that 11%, 21% and 34% of all countries can be interpreted as currently misclassified in the development bins due to the three sources of data error, respectively. The authors suggest that the United Nations should discontinue the practice of classifying countries into development bins because - they claim - the cut-off values seem arbitrary, can provide incentives for strategic behavior in reporting official statistics, and have the potential to misguide politicians, investors, charity donors and the public who use the HDI at large.[citation needed] In 2010 the UNDP reacted to the criticism and updated the thresholds to classify nations as low, medium, and high human development countries. In a comment to The Economist in early January 2011, the Human Development Report Office responded[32] to a January 6, 2011 article in the magazine[33] which discusses the Wolff et al. paper. The Human Development Report Office states that they undertook a systematic revision of the methods used for the calculation of the HDI and that the new methodology directly addresses the critique by Wolff et al. in that it generates a system for continuous updating of the human development categories whenever formula or data revisions take place.

^Mean years of schooling (of adults) (years) is a calculation of the average number of years of education received by people ages 25 and older in their lifetime based on education attainment levels of the population converted into years of schooling based on theoretical duration of each level of education attended. Source: Barro, R. J.; Lee, J.-W. (2010). "A New Data Set of Educational Attainment in the World, 1950–2010". NBER Working Paper No. 15902.

^(ESYI is a calculation of the number of years a child is expected to attend school, or university, including the years spent on repetition. It is the sum of the age-specific enrollment ratios for primary, secondary, post-secondary non-tertiary and tertiary education and is calculated assuming the prevailing patterns of age-specific enrollment rates were to stay the same throughout the child's life. Expected years of schooling is capped at 18 years. (Source: UNESCO Institute for Statistics (2010). Correspondence on education indicators. March. Montreal.)

^ abTaiwan's government calculated its HDI to be 0.882, based on 2010 new methodology of UNDP. "2011中華民國人類發展指數 (HDI)"(PDF) (in Chinese). Directorate General of Budget, Accounting and Statistics, Executive Yuan, R.O.C. 2011. Retrieved 2011-11-21.

^ abThe UN does not recognize the Republic of China (Taiwan) as a sovereign state. The HDI report does not include Taiwan as part of the People's Republic of China when calculating China's figures. Taiwan's government calculated its HDI to be 0.882, based on 2010 new methodology of UNDP. "2011中華民國人類發展指數 (HDI)"(PDF) (in Chinese). Directorate General of Budget, Accounting and Statistics, Executive Yuan, R.O.C. 2011. Retrieved 2011-11-21.